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Minnesota Soybean Business

Seed needs: Experts offer advice on 2024 soybean varieties

November-December 2023

Purchasing soybean seed isn’t as simple as running into the grocery store for a gallon of milk. Luckily, there are experts and resources available to help soybean growers make the best decisions for their operations. Though there is a lengthy list of factors to consider when selecting varieties, there are a few key characteristics to keep in mind.

‘Know your ground’

All soil is not created equal. In some parts of Minnesota, farmers have sandy soil while other growers work with clay. And the differences don’t stop there. Differences in soil – whether drastic or minimal – impact which soybean varieties will flourish.

“The first step in selecting your product is to know your ground,” said Bob Lindeman, a director with the Minnesota Soybean Growers Association and a seed salesman with Rob-See-Co. “You need to know your soil. Talk to a seed dealer or people that know what kind of soil you’re going to put these beans on, because they’re going to have some good recommendations.”

Not only do growers from different parts of Minnesota work with different types of soil, but individual farmers may have multiple soil types on their farm.

“Every piece of ground is its own island,” Minnesota Soybean Director of Research David Kee said. “It’s important to talk with your advisor about your needs for that particular piece of ground and how that piece of ground fits into your planting and management scheme.”

Battling SCN

As the most destructive soybean pest in the U.S., soybean cyst nematode (SCN) is a battle that farmers continually fight. Because there is no way to eliminate SCN once it’s in a field, one of the most effective management practices is planting resistant varieties.

Yield lost from soybean cyst nematode can exceed 30 percent.

“SCN resistance is really important,” said Aaron Lorenz, a University of Minnesota soybean breeder. “A key thing with SCN resistance is that if you feel like your soybeans aren’t yielding quite as well as they should be and you’ve grown the same source of SCN resistance for many years, you may have resistance breakdown where the SCN populations in your field have slowly evolved to overcome that resistance.”

Found in 64 soybean-growing counties across Minnesota, SCN has been showing some resistance to PI 88788, which growers have widely used to combat the pest.

“PI 88788 was doing a pretty good job for a number of years on SCN,” Lindeman said. “Now, companies are focusing a little bit more on Peking and that gene because there has been resistance to the old gene that we’ve been using. And some of the yields have bumped up on the Peking compared to when it was first introduced.”

Rotating resistance packages is one of the best longterm SCN management practices, with crop rotation another important tool growers have in their toolbox.

“As a general principle, producers should be rotating their sources of resistance,” Lorenz said. “Use some PI 88788 and then make sure you work in some Peking resistance into the rotation as well.”

Combating white mold

Another disease that Minnesota growers need to combat is white mold.

“For Minnesota as a whole, white mold is a big concern,” said Rick Swenson, lead agronomist for Peterson Farms Seed. “There are a few factors to pay attention to when choosing a variety that will resist white mold, including plant structure, standability rating and row spacing.”

Strongly affected by environmental conditions, white mold thrives in cool and moist conditions at the time of flowering. Though no soybean variety is completely resistant, there are varieties available that are partially resistant, lowering the chance of disease incidence. Additionally, canopy management is a method growers can use to mitigate the risk of white mold.

Canopy management is one way Minnesota farmers can address white mold on their soybean crop.

“If you’re growing a big structured bean with a little bit later maturity, you can usually get by planting a little bit lighter; I’m saying go down to 120,000 or 130,000 plants per acre to battle some of the diseases like white mold,” Lindeman said. “If you thin that out and let some air move through that canopy a little more, you can combat some diseases. But if you’re growing a small-structured plant, I like to keep the plant population up a little bit, in the 140,000 range, because you don’t have as much plant filling the row.”

Mitigating IDC Iron deficiency chlorosis (IDC) is another headache soybean growers contend with each year.

“IDC has been getting worse and, in some areas, it could be a salt buildup because we’ve had so much drought and haven’t had a chance to rinse any of the salt out,” Lindeman said. “There are varieties that have salt excluders in them that would probably benefit some growers.” K

eeping soil nitrate levels in mind is also important. And along with choosing a resistant variety, iron chelate products are another option that can help mitigate the effects of IDC.

“Nitrate accumulation is what really caused a big problem with IDC compared to last year because we’re four years into a drought,” Kee said. Fortunately for soybean producers, the Minnesota Soybean Research & Promotion Council and the soy checkoff invest resources by sponsoring projects addressing these yield-robbing pests and diseases.

“From pest management to genetics, the checkoff supports research that helps us make more informed decisions when we’re making those critical seed decisions for the year ahead,” Council Director Gene Stoel said.

Switch it up When choosing soybean varieties for 2024, growers should avoid putting all their eggs in one basket.

“You’ve got too many acres to plant just a single variety,” Kee said.

While there isn’t a set recommended number of varieties to plant, selecting three to five varieties seems to be the sweet spot for many.

“I recommend planting somewhere around five varieties,” said Swenson, who sits on the Otter Tail-Grant Corn and Soybean Growers board. “For beans, I don’t mind replacing two out of the five varieties just because of the crop rotation and because the life cycle might only be three to five years. But we are starting to go the other way where we are keeping varieties around a little bit longer than we have even in the last five years.”

If a grower purchases seed from multiple companies, make sure to pay close attention to the variety name. Just because the brand name is different, doesn’t mean the variety is different.

“You don’t want to buy two varieties from two different companies and then inadvertently be growing the same variety,” Lorenz said.

Selecting soybean seed isn’t a one-size-fits-all process. When in doubt, talk to local seed dealers, agronomists and researchers to learn about the latest varieties and which issues are expected to be most prevalent during the 2024 growing season.

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